1. Field of Invention
The present invention relates to a glass substrate carrier assembly, and more particularly to the glass substrate carrier assembly that removes static electricity.
2. Description of the Related Art
Liquid crystal displays (LCDs) have gradually come to dominate the display market because the LCD is thin and light and has a glass substrate. A process for producing the LCD comprises forming thin-film transistors and circuits on the glass substrate by using a photolithography process. The photolithography process coats a layer of a photoresist homogeneously on the glass substrate and then transfers a pattern from a mask to the photoresist layer before conducting a development process.
A current method to coat the glass substrate with photoresist mounts the glass substrate on a photoresist spin coater and dispense a specific amount of photoresist on the center of the upper surface of the glass substrate. Finally, the photoresist spin coater is operated at a high speed to generate a centrifugal force and rotate the glass substrate. The centrifugal force causes the photoresist to diffuse radially from the center to the edge of the glass substrate, so the photoresist covers the whole upper surface and solidifies.
After the coating procedure, the edge of the glass substrate often has burrs generated by solidifying photoresist being slung out from the edge of the glass substrate. Consequently, the glass substrate must be transferred from the photoresist spin coater to de-burring device by a carrier assembly to remove the burrs. The carrier assembly comprises a shelf and two brackets. The shelf can move horizontally. The brackets protrude from the shelf longitudinally, face each other and has multiple pickup caps mounted on the brackets. Each bracket connects to a vacuum pump by a tube, and the vacuum pump generates a suction in the pickup caps to hold the glass substrate against the pickup caps. The suction applied to the pickup caps causes static electricity to build up in the pickup caps.
After the glass arrives at the de-burring device, the glass substrate detaches from the pickup cap. However, the static electricity produced by the pickup cap is 15-16 kilovolt (KV) that easily damages semiconductor elements and circuits on the glass substrate and may even damage the glass substrate.
To overcome the shortcomings, the present invention provides a glass substrate carrier assembly to mitigate or obviate the aforementioned problems.